Re: [PATCH RFC 77/77] vxge: Update MSI/MSI-X interrupts enablement code

Jon Mason
2013-10-03T00:29:42Z

On Wed, Oct 02, 2013 at 12:49:33PM +0200, Alexander Gordeev wrote:
> As result of recent re-design of the MSI/MSI-X interrupts enabling
> pattern this driver has to be updated to use the new technique to
> obtain a optimal number of MSI/MSI-X interrupts required.
>
> Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
> ---
> drivers/net/ethernet/neterion/vxge/vxge-main.c | 36 ++++++++++-------------
> 1 files changed, 16 insertions(+), 20 deletions(-)
>
> diff --git a/drivers/net/ethernet/neterion/vxge/vxge-main.c b/drivers/net/ethernet/neterion/vxge/vxge-main.c
> index b81ff8b..b4d40dd 100644
> --- a/drivers/net/ethernet/neterion/vxge/vxge-main.c
> +++ b/drivers/net/ethernet/neterion/vxge/vxge-main.c
> @@ -2297,7 +2297,21 @@ static int vxge_alloc_msix(struct vxgedev *vdev)
> int msix_intr_vect = 0, temp;
> vdev->intr_cnt = 0;
>
> -start:
> + ret = pci_msix_table_size(vdev->pdev);
> + if (ret < 0)
> + goto alloc_entries_failed;
> +
> + if (ret < (vdev->no_of_vpath * 2 + 1)) {
> + if ((max_config_vpath != VXGE_USE_DEFAULT) || (ret < 3)) {
> + ret = -ENOSPC;
> + goto alloc_entries_failed;
> + }
> + /* Try with less no of vector by reducing no of vpaths count */
> + temp = (ret - 1)/2;
> + vxge_close_vpaths(vdev, temp);
> + vdev->no_of_vpath = temp;
> + }

The original code was ugly (not my code, so I can say that). I'd like
to see it a little stream lined. Something like:

vdev->intr_cnt = pci_msix_table_size(vdev->pdev);

if (vdev->intr_cnt % 2 == 0)
vdev->intr_cnt--;

if (vdev->intr_cnt < 3 || max_config_vpath != VXGE_USE_DEFAULT)
goto alloc_entries_failed;

if (vdev->intr_cnt != vdev->no_of_vpath * 2 + 1) {
vxge_close_vpaths(vdev, vdev->intr_cnt / 2);
vdev->no_of_vpath = vdev->intr_cnt / 2;
}

> +
> /* Tx/Rx MSIX Vectors count */
> vdev->intr_cnt = vdev->no_of_vpath * 2;
>
> @@ -2347,25 +2361,7 @@ start:
> vdev->vxge_entries[j].in_use = 0;
>
> ret = pci_enable_msix(vdev->pdev, vdev->entries, vdev->intr_cnt);
> - if (ret > 0) {
> - vxge_debug_init(VXGE_ERR,
> - "%s: MSI-X enable failed for %d vectors, ret: %d",
> - VXGE_DRIVER_NAME, vdev->intr_cnt, ret);
> - if ((max_config_vpath != VXGE_USE_DEFAULT) || (ret < 3)) {
> - ret = -ENOSPC;
> - goto enable_msix_failed;
> - }
> -
> - kfree(vdev->entries);
> - kfree(vdev->vxge_entries);
> - vdev->entries = NULL;
> - vdev->vxge_entries = NULL;
> - /* Try with less no of vector by reducing no of vpaths count */
> - temp = (ret - 1)/2;
> - vxge_close_vpaths(vdev, temp);
> - vdev->no_of_vpath = temp;
> - goto start;
> - } else if (ret < 0)
> + if (ret)
> goto enable_msix_failed;

Nit, space here please.

> return 0;
>
> --
> 1.7.7.6
>